EP0467042B1 - Process for producing a gas purging brick with directional porosity and high infiltration resistance for metallurgical vessels - Google Patents

Process for producing a gas purging brick with directional porosity and high infiltration resistance for metallurgical vessels Download PDF

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Publication number
EP0467042B1
EP0467042B1 EP91108222A EP91108222A EP0467042B1 EP 0467042 B1 EP0467042 B1 EP 0467042B1 EP 91108222 A EP91108222 A EP 91108222A EP 91108222 A EP91108222 A EP 91108222A EP 0467042 B1 EP0467042 B1 EP 0467042B1
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EP
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Prior art keywords
accordance
plug
impregnating
slip
matrix material
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EP91108222A
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German (de)
French (fr)
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EP0467042A2 (en
EP0467042A3 (en
Inventor
Lorenz Dötsch
Erich Renfordt
Helmut Dipl.-Ing. Preyer
Jean-Louis Retrayt
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Veitsch Radex GmbH and Co OG
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Veitsch Radex GmbH and Co OG
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
    • B22D1/002—Treatment with gases
    • B22D1/005—Injection assemblies therefor
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/013—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics containing carbon
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/636—Polysaccharides or derivatives thereof
    • C04B35/6365—Cellulose or derivatives thereof

Definitions

  • the invention relates to a method for producing a gas purging plug with increased resistance to infiltration with directed porosity for use in metallurgical melting vessels.
  • flushing stones which serve to supply gases and / or solids in metallurgical melts, have long been known.
  • the RADEX-Rundschau, 1987, 288 provides a comprehensive overview.
  • Gas flushing blocks with "directed porosity" in particular have recently become established.
  • These flushing elements are characterized by channels within the refractory, ceramic matrix material, which run from the gas supply side to the gas outlet side.
  • the channels are fed with gas from a central gas supply, but possibly also with gas / solid mixtures.
  • the object of the invention is to offer a gas purging plug with directed porosity or to provide a corresponding manufacturing process which leads to purging plugs with increased resistance to infiltration.
  • the invention is based on the knowledge that improved resistance to infiltration can be achieved above all by impregnating the matrix material of the sink (outside the pore channels).
  • the invention has recognized that special measures must be taken for this purpose in order to prevent infiltration of the infiltration medium into the open pore channels of the previously produced sink with directed porosity.
  • the invention describes a method with the features of claim 1.
  • Advantageous embodiments are specified in the subclaims and in the other application documents.
  • the method is based on a conventional manufactured sink with directed porosity.
  • the sink may be necessary to subsequently anneal the sink (for example at temperatures between 350 and 900 degrees Celsius), burn (usually above 1200 degrees Celsius) or first anneal and then burn.
  • the sink is then subjected to an impregnation treatment, it being important that during the impregnation treatment the pore channels are temporarily filled with a material, so that the impregnation medium can only penetrate into the open pore volume of the matrix material and at least partially fill it, while it does not fill the pore channels penetrates because these are filled with the material during the impregnation treatment.
  • the impregnation treatment is preferably carried out using pressure and / or vacuum in a corresponding treatment vessel, where the sink stones are immersed, for example.
  • the impregnation medium If, for example, pitch or tar is used as the impregnation medium, it is necessary to subsequently drive out the volatile constituents, which is why the sink should at least subsequently be tempered. Even during this process step, the pore channels remain provisionally filled with the material, so that the impregnation medium cannot then penetrate into the pore channels and block them.
  • the invention proposes various alternative embodiments for carrying out the impregnation treatment.
  • a slip having thixotropic properties can be converted into a more or less low-viscosity state in the cold state, just like, for example, heated pitch.
  • its viscosity can be reduced so that the open pore volume of the matrix material of the sink is more or less completely filled before - after switching off an appropriate mechanical / physical excitation unit - the slip stiffens again due to its thixotropic properties and the open pore volume (with the exception of the pore channels) then closes reliably.
  • the slip preferably contains an additive which enhances the thixotropic properties.
  • These agents include, for example, methyl cellulose, but also other wetting agents such as alkyl, aryl, polyoxyethanol.
  • the mechanical / physical excitation units provided to liquefy the thixotropic slip can, for example, be mechanical vibrators or ultrasonic devices.
  • the products to be impregnated can be placed in a kettle filled with the slip. Then either the entire device is then moved (shaken) or the slurry is physically loaded via an ultrasound device, so that the thixotropic framework of the slurry collapses in any case and the slurry can penetrate into the open pore volume.
  • the impregnation can be additionally supported by a pressure / vacuum device, as is known from the prior art.
  • tar or pitch impregnation processes can also be used, which are known in other contexts, for example in the case of refractory ceramic stones.
  • the pore channels - as described - must be filled so that no impregnation medium penetrates there and clogs the channels.
  • Different materials can be used to fill the pore channels. The choice of materials However, it must be done so that there is no permanent connection between the material and the ceramic matrix material of the sink. Examples can be given as follows: powdery, inert substances which are filled into the pore channels, the open ends of the pore channels then being sealed, for example by fitting a plate.
  • solid rod or strip-shaped elements can also be used, for example made of paper, cardboard, plastic or metal.
  • these elements can be coated on their surface with a lubricant, for example wax, paraffin, oil or graphite.
  • a lubricant for example wax, paraffin, oil or graphite.
  • the cross section of these elements should be the same or slightly smaller than the cross section of the pore channels, so that on the one hand they completely fill the pore channels, but on the other hand they are easy to remove later.
  • the method according to the invention enables the production of flushing stones with directed porosity, which have a significantly increased infiltration resistance compared to known flushing elements of the same type. If the washing stones are pressed, in particular isostatically pressed washing stones, the mechanical stability and resistance to infiltration are additionally improved due to the higher density of the matrix material.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • Structural Engineering (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Powder Metallurgy (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Abstract

The invention relates to a process for producing a bubble brick having enhanced infiltration resistance and directional porosity for use in metallurgical melting vessels, the matrix material of the bubble brick being subjected to an impregnation treatment.

Description

Die Erfindung betrifft ein Verfahren zur Herstellung eines Gasspülsteins erhöhter Infiltrationsbeständigkeit mit gerichteter Porosität zur Anwendung in metallurgischen Schmelzgefäßen.The invention relates to a method for producing a gas purging plug with increased resistance to infiltration with directed porosity for use in metallurgical melting vessels.

Derartige Spülsteine, die zur Zuführung von Gasen und/oder Feststoffen in metallurgische Schmelzen dienen, sind seit langem bekannt. Eine umfassende Übersicht gibt die RADEX-Rundschau, 1987, 288. In letzter Zeit haben sich insbesondere Gasspülsteine mit "gerichteter Porosität" durchgesetzt. Diese Spülelemente sind charakterisiert durch Kanäle innerhalb des feuerfesten, keramischen Matrixmaterials, die von der Gaszuführseite zur Gasaustrittsseite verlaufen.Such flushing stones, which serve to supply gases and / or solids in metallurgical melts, have long been known. The RADEX-Rundschau, 1987, 288 provides a comprehensive overview. Gas flushing blocks with "directed porosity" in particular have recently become established. These flushing elements are characterized by channels within the refractory, ceramic matrix material, which run from the gas supply side to the gas outlet side.

Die Kanäle werden von einer zentralen Gaszuführung mit Gas, gegebenenfalls aber auch mit Gas-/Feststoffgemischen gespeist.The channels are fed with gas from a central gas supply, but possibly also with gas / solid mixtures.

Obwohl sich derartige Gasspülsteine seit Jahren in großem Umfang bewährt haben wird im Rahmen zunehmender Qualitätsanforderungen auch der Wunsch nach Erhöhung der Infiltrationsbeständigkeit dieser Spüleinrichtungen gegen metallurgische Schmelzen geäußert.Although such gas purging plugs have proven themselves on a large scale for years, the desire to increase the infiltration resistance of these purging devices against metallurgical melts is also expressed in the context of increasing quality requirements.

Entsprechend liegt der Erfindung die Aufgabe zugrunde, einen Gasspülstein mit gerichteter Porosität anzubieten beziehungsweise ein entsprechendes Herstellungsverfahren zur Verfügung zu stellen, das zu Spülsteinen erhöhter Infiltrationsbeständigkeit führt.Accordingly, the object of the invention is to offer a gas purging plug with directed porosity or to provide a corresponding manufacturing process which leads to purging plugs with increased resistance to infiltration.

Der Erfindung liegt die Erkenntnis zugrunde, daß eine verbesserte Infiltrationsbeständigkeit vor allem durch eine Imprägnierung des Matrixmaterials des Spülsteins (außerhalb der Porenkanäle) erreicht werden kann. Dabei hat die Erfindung erkannt, daß zu diesem Zweck besondere Maßnahmen getroffen werden müssen, um eine Infiltration des Infiltrationsmediums in die offenen Porenkanäle des zuvor hergestellten Spülsteins mit gerichteter Porosität zu verhindern.The invention is based on the knowledge that improved resistance to infiltration can be achieved above all by impregnating the matrix material of the sink (outside the pore channels). The invention has recognized that special measures must be taken for this purpose in order to prevent infiltration of the infiltration medium into the open pore channels of the previously produced sink with directed porosity.

In ihrer allgemeinsten Ausführungsform beschreibt die Erfindung ein Verfahren mit den Merkmalen des Anspruches 1. Vorteilhafte Ausführungsformen sind in den Unteransprüchen sowie den sonstigen Anmeldungsunterlagen angegeben.In its most general embodiment, the invention describes a method with the features of claim 1. Advantageous embodiments are specified in the subclaims and in the other application documents.

Zunächst wird dem Verfahren ein auf konventionelle Weise hergestellter Spülstein mit gerichteter Porosität zugrundegelegt.First of all, the method is based on a conventional manufactured sink with directed porosity.

Je nach Herstellungsverfahren (gegossener oder gepreßter Spülstein) kann es notwendig sein, den Spülstein anschließend zu tempern (zum Beispiel bei Temperaturen zwischen 350 und 900 Grad Celsius), zu brennen (meist oberhalb 1200 Grad Celsius) oder zunächst zu tempern und anschließend zu brennen.Depending on the manufacturing process (cast or pressed sink), it may be necessary to subsequently anneal the sink (for example at temperatures between 350 and 900 degrees Celsius), burn (usually above 1200 degrees Celsius) or first anneal and then burn.

Der Spülstein wird danach einer Imprägnierungsbehandlung unterworfen, wobei wichtig ist, daß während der Imprägnierungsbehandlung die Porenkanäle temporär mit einem Material gefüllt sind, so daß das Imprägniermedium nur in das offene Porenvolumen des Matrixmaterials eindringen kann und dieses zumindest teilweise ausfüllt, während es nicht in die Porenkanäle eindringt, weil diese mit dem Material während der Imprägnierungsbehandlung ausgefüllt sind.The sink is then subjected to an impregnation treatment, it being important that during the impregnation treatment the pore channels are temporarily filled with a material, so that the impregnation medium can only penetrate into the open pore volume of the matrix material and at least partially fill it, while it does not fill the pore channels penetrates because these are filled with the material during the impregnation treatment.

Die Imprägnierungsbehandlung erfolgt vorzugsweise unter Anwendung von Druck und/oder Vakuum in einem entsprechenden Behandlungsgefäß, wo die Spülsteine zum Beispiel eingetaucht werden.The impregnation treatment is preferably carried out using pressure and / or vacuum in a corresponding treatment vessel, where the sink stones are immersed, for example.

Wird als Imprägniermedium zum Beispiel Pech oder Teer verwendet, ist es notwendig, die flüchtigen Bestandteile anschließend auszutreiben, weshalb der Spülstein anschließend zumindest getempert werden sollte. Auch während dieses Verfahrensschrittes bleiben die Porenkanäle vorläufig mit dem Material gefüllt, so daß das Imprägniermedium auch dann nicht in die Porenkanäle eindringen und diese verstopfen kann.If, for example, pitch or tar is used as the impregnation medium, it is necessary to subsequently drive out the volatile constituents, which is why the sink should at least subsequently be tempered. Even during this process step, the pore channels remain provisionally filled with the material, so that the impregnation medium cannot then penetrate into the pore channels and block them.

Erst danach wird das Material wieder aus den Porenkanälen entnommen. Der imprägnierte Spülstein ist dann einsatzbereit; bei Bedarf kann er anschließend aber auch noch gebrannt werden, insbesondere wenn er zuvor noch nicht gebrannt wurde.Only then is the material removed from the pore channels. The impregnated sink is then ready for use; If necessary, it can also be burned afterwards, especially if it was previously has not yet been burned.

Zur Ausführung der Imprägnierungsbehandlung schlägt die Erfindung verschiedene alternative Ausführungsformen vor.The invention proposes various alternative embodiments for carrying out the impregnation treatment.

Neben der erwähnten Teer- oder Pech-Tränkung, die in der Regel bei Temperaturen zwischen 150 und 250 Grad Celsius stattfindet kann aber auch eine mechanisch/physikalische Imprägnierungsbehandlung erfolgen.In addition to the tar or pitch impregnation mentioned, which usually takes place at temperatures between 150 and 250 degrees Celsius, mechanical / physical impregnation treatment can also be carried out.

Es wurde nämlich festgestellt, daß ein, thixotrope Eigenschaften aufweisender Schlicker, in kaltem Zustand, ebenso wie zum Beispiel erhitztes Pech, in einen mehr oder weniger niedrig viskosen Zustand überführt werden kann. Je nach Auswahl der Komponenten des Schlickers kann seine Viskosität dabei so abgesenkt werden, daß das offene Porenvolumen des Matrixmaterials des Spülsteins mehr oder weniger vollständig verfüllt wird, bevor - nach Abschaltung einer entsprechenden mechanischen/physikalischen Erregereinheit - der Schlicker aufgrund seiner thixotropen Eigenschaften wieder ansteift und das offene Porenvolumen (mit Ausnahme der Porenkanäle) danach zuverlässig verschließt.It has been found that a slip having thixotropic properties can be converted into a more or less low-viscosity state in the cold state, just like, for example, heated pitch. Depending on the selection of the components of the slip, its viscosity can be reduced so that the open pore volume of the matrix material of the sink is more or less completely filled before - after switching off an appropriate mechanical / physical excitation unit - the slip stiffens again due to its thixotropic properties and the open pore volume (with the exception of the pore channels) then closes reliably.

Die Auswahl des thixotropen Schlickers erfolgt unter Berücksichtigung folgender Kriterien:

  • die Korngröße des Feststoffanteils des Schlickers muß auf die Größe der zu verfüllenden Poren abgestellt werden, das heißt, sie muß kleiner sein. Im bevorzugten Bereich sollte die mittlere Teilchengröße der Feststoffkomponente des Schlickers maximal 1/5, vorzugsweise maximal 1/10 des mittleren Durchmessers der offenen Poren des Matrixmaterials des Spülsteins betragen. Je feiner das Schlickermaterial ist, umso vollständiger kann es auch kleinere Poren verfüllen. Bei einem mittleren Porendurchmesser von zum Beispiel 30 µm sollte der Feststoffanteil dann in einer Kornfraktion kleiner 3 µm vorliegen.
  • Die Feuerfestkomponente ist vorzugsweise eine keramische Komponente, die basisch ist, wenn das Matrixmaterial des Spülsteins basisch ist beziehungsweise sauer ist, wenn ein saures Matrixmaterial zur Verfügung steht. Als Beispiele können mikronisierter Korund oder feinteiliger Magnesit angegeben werden. Natürlich können auch amphotere Stoffe eingesetzt werden.
  • Zur Aufbereitung des Schlickers enthält dieser neben der feuerfesten keramischen Komponente auch eine gerüstbildende und/oder Flüssigkeitskomponente, die kohlenstoffhaltig sein soll und beispielsweise aus einem Harz bestehen kann. Die Kohlenstoff-Komponente des Harzes vercrackt bei einer anschließenden Temperaturbehandlung (Temperung) und bildet ein Kohlenstoff-Gerüst für die feuerfesten keramischen Partikel, was sich stabilitätserhöhung für das Imprägniermedium auswirkt.
The thixotropic slip is selected taking the following criteria into account:
  • the grain size of the solids content of the slip must be adjusted to the size of the pores to be filled, that is to say it must be smaller. In the preferred range, the average particle size of the solid component of the slip should be at most 1/5, preferably at most 1/10 of the average diameter of the open pores of the matrix material of the sink. The finer the slip material, the more completely it can fill smaller pores. With an average pore diameter of 30 µm, for example, the solids content should be in a grain fraction of less than 3 µm.
  • The refractory component is preferably a ceramic component that is basic when the matrix material of the sink is basic or acidic when an acidic matrix material is available. Micronized corundum or finely divided magnesite can be given as examples. Of course, amphoteric substances can also be used.
  • In order to process the slip, in addition to the refractory ceramic component, the slip also contains a framework-forming and / or liquid component which is said to contain carbon and can, for example, consist of a resin. The carbon component of the resin cracks during a subsequent temperature treatment (tempering) and forms a carbon framework for the refractory ceramic particles, which has an impact on the stability of the impregnation medium.

Vorzugsweise enthält der Schlicker ein Zusatzmittel, das die thixotropen Eigenschaften verstärkt. Zu diesen Mitteln gehören beispielse Methylzellulose, aber auch andere Netzmittel wie Alkyl-, Aryl-, Polyoxiäthanol.The slip preferably contains an additive which enhances the thixotropic properties. These agents include, for example, methyl cellulose, but also other wetting agents such as alkyl, aryl, polyoxyethanol.

Die zur Verflüssigung des thixotropen Schlickers vorgesehenen mechanischen/physikalischen Erregereinheiten können beispielsweise mechanische Rüttler oder Ultraschalleinrichtungen sein. So können die zu imprägnierenden Produkte zum Beispiel in einen, mit dem Schlicker gefüllten Kessel eingelegt werden. Anschließend wird dann entweder die gesamte Einrichtung bewegt (gerüttelt) oder der Schlicker wird über eine Ultraschalleinrichtung physikalisch beaufschlagt, so daß auf jeden Fall das thixotrope Gerüst des Schlickers zusammenbricht und dieser in das offene Porenvolumen eindringen kann. Durch eine Druck-/Vakuumeinrichtung, wie sie aus dem Stand der Technik bekannt ist, kann die Imprägnierung zusätzlich unterstützt werden.The mechanical / physical excitation units provided to liquefy the thixotropic slip can, for example, be mechanical vibrators or ultrasonic devices. For example, the products to be impregnated can be placed in a kettle filled with the slip. Then either the entire device is then moved (shaken) or the slurry is physically loaded via an ultrasound device, so that the thixotropic framework of the slurry collapses in any case and the slurry can penetrate into the open pore volume. The impregnation can be additionally supported by a pressure / vacuum device, as is known from the prior art.

Der Vorteil dieses Imprägnierungsverfahrens besteht darin, daß die Imprägnierung im kalten Zustand erfolgt, also zum Beispiel bei Raumtemperatur. Hierdurch können Energiekosten eingespart werden. Eine nachfolgende Temperung zur Verdampfung der flüchtigen Bestandteile kann entfallen. Umweltbelastende Emissionen treten nicht auf.The advantage of this impregnation process is that the impregnation takes place in the cold state, for example at room temperature. This can save energy costs. A subsequent tempering to evaporate the volatile constituents can be omitted. There are no polluting emissions.

Wie oben ausgeführt können aber auch Teer- oder Pech-Imprägnierungsverfahren eingesetzt werden, die in anderem Zusammenhang, zum Beispiel bei feuerfesten keramischen Steinen, bekannt sind.As stated above, however, tar or pitch impregnation processes can also be used, which are known in other contexts, for example in the case of refractory ceramic stones.

Während der Imprägnierbehandlung sowie der gegebenenfalls sich anschließenden Temperung müssen die Porenkanäle - wie beschrieben - verfüllt sein, damit kein Imprägniermedium dort eindringt und die Kanäle verstopft. Zum Ausfüllen der Porenkanäle können unterschiedliche Materialien eingesetzt werden. Die Materialauswahl hat jedoch so zu erfolgen, daß keine unlösbare Verbindung des Materials mit dem keramischen Matrixmaterial des Spülsteins entsteht. Als Beispiele können angegeben werden: pulverförmige, inerte Stoffe, die in die Porenkanäle eingefüllt werden, wobei die offenen Enden der Porenkanäle dann abgedichtet werden, zum Beispiel durch Aufsetzen einer Platte. Ebenso können aber auch feste stab- oder streifenförmige Elemente eingesetzt werden, zum Beispiel aus Papier, Pappe, Kunststoff oder Metall. Um das spätere Herausziehen dieser Elemente zu erleichtern, können sie auf ihrer Oberfläche mit einem Gleitmittel beschichtet sein, zum Beispiel Wachs, Paraffin, Öl oder Graphit. Der Querschnitt dieser Elemente sollte gleich oder geringfügig kleiner als der Querschnitt der Porenkanäle sein, so daß sie einerseits die Porenkanäle vollständig ausfüllen, andererseits aber später wieder leicht entnehmbar sind. Zum Herausziehen der Elemente ist es - je nach verwendetem Material - vorteilhaft, diese zuvor zu erwärmen. Bei metallischen Elementen hat sich eine induktive Erwärmung als besonders vorteilhaft herausgestellt.During the impregnation treatment and any subsequent tempering, the pore channels - as described - must be filled so that no impregnation medium penetrates there and clogs the channels. Different materials can be used to fill the pore channels. The choice of materials However, it must be done so that there is no permanent connection between the material and the ceramic matrix material of the sink. Examples can be given as follows: powdery, inert substances which are filled into the pore channels, the open ends of the pore channels then being sealed, for example by fitting a plate. However, solid rod or strip-shaped elements can also be used, for example made of paper, cardboard, plastic or metal. In order to facilitate the later removal of these elements, they can be coated on their surface with a lubricant, for example wax, paraffin, oil or graphite. The cross section of these elements should be the same or slightly smaller than the cross section of the pore channels, so that on the one hand they completely fill the pore channels, but on the other hand they are easy to remove later. To pull out the elements, it is advantageous - depending on the material used - to warm them up beforehand. In the case of metallic elements, inductive heating has proven to be particularly advantageous.

Das erfindungsgemäße Verfahren ermöglicht die Herstellung von Spülsteinen mit gerichteter Porosität, die gegenüber bekannten gattungsgleichen Spülelementen eine deutlich erhöhte Infiltrationsbeständigkeit aufweisen. Handelt es sich bei den Spülsteinen um gepreßte, insbesondere isostatisch gepreßte Spülsteine, wird die mechanische Stabilität und Infiltrationsbeständigkeit zusätzlich aufgrund der höheren Dichte des Matrixmaterials verbessert.The method according to the invention enables the production of flushing stones with directed porosity, which have a significantly increased infiltration resistance compared to known flushing elements of the same type. If the washing stones are pressed, in particular isostatically pressed washing stones, the mechanical stability and resistance to infiltration are additionally improved due to the higher density of the matrix material.

Claims (22)

  1. Process for producing a gas pursing plug with increased resistance to infiltration and oriented porosity for use in metallurgical melting crucibles, comprising the following steps:
    1.1 a plug is manufactured from a refractory ceramic matrix material in a known manner, forming oriented pore canals, which extend between the gas inlet end and gas discharge end;
    1.2 the plug is subsequently tempered if desired, fired, or tempered and fired;
    1.3 the plug is subsequently subjected to an impregnating treatment, during which the pore canals are temporarily filled with a material, and the impregnating medium penetrates into the open pore volume of the matrix material and fills this at least partially;
    1.4 the impregnated plug is subsequently tempered if desired before
    1.5 the material is subsequently again removed from the pore canals.
  2. Process in accordance with claim 1, in which a pressed plug is used as the plug.
  3. Process in accordance with claim 2, in which an isostatically pressed plug is used as the plug.
  4. Process in accordance with one of claims 1 to 3, in which the tempering is carried out at a temperature between 350°C and 900°C prior to the impregnating treatment.
  5. Process in accordance with one of claims 1 to 4, in which a slip which possesses thixotropic properties and consists of a fine particulate refractory ceramic material and a carbon-containing component is used.
  6. Process in accordance with claim 5, characterized in that a slip whose solids content is at least 40 wt.% is used.
  7. Process in accordance with claim 5 or 6, characterized in that a slip whose solid component has a maximum particle size corresponding to 1/5 of the average pore diameter of the plug is used.
  8. Process in accordance with claim 7, characterized in that a slip whose solid component has a maximum particle size corresponding to 1/10 of the average pore diameter of the plug is used.
  9. Process in accordance with one of claims 5 to 8, characterized in that a slip containing a thixotropy-inducing agent is used.
  10. Process in accordance with claim 9, characterized in that a methylcellulose is used as the thixotropy-inducing agent.
  11. Process in accordance with one of claims 5 to 10, characterized in that a resin, e.g., a phenolic resin or a novolac resin, is used as the carbon-containing component.
  12. Process in accordance with one of claims 5 to 11, characterized in that the refractory component of the impregnating medium for a plug made from a basic matrix material is basic and that for a plug made from an acidic matrix material is acidic.
  13. Process in accordance with one of claims 5 to 12, in which the slip is liquefied by means of a mechanical and/or physical exciting unit and introduced into the open pore volume of the plug -- by applying pressure and/or vacuum if desired -- and the exciting unit is turned off after reaching the predetermined degree of filling, and the impregnating agent begins to stiffen at the same time.
  14. Process in accordance with one of claims 1 to 4 characterized in that a carbon-containing component is used as the impregnating medium.
  15. Process in accordance with claim 14, in which pitch or tar is used as the impregnating medium.
  16. Process in accordance with claim 14 or 15, characterized in that the impregnating medium is introduced into the open pore volume of the matrix material of the plug in viscous form under pressure and/or vacuum.
  17. Process in accordance with one of claims 1 to 16 characterized in that the impregnated plug is tempered at a temperature at which the volatile components of the impregnating medium evaporate.
  18. Process in accordance with one of claims 1 to 17 characterized in that the pore canals are filled with a corresponding heat-resistant material during the impregnating treatment as well as the subsequent tempering.
  19. Process in accordance with one of claims 1 to 18, characterized in that during the impregnating treatment and the subsequent tempering that may be performed, the pore canals are filled with the same material which was used to mold the pore canals during the manufacture of the plug.
  20. Process in accordance with one of claims 1 to 19, characterized in that a plug whose pore canals are resealed prior to the impregnating treatment is used.
  21. Process in accordance with one of claims 1 to 20, which during the impregnating treatment and the subsequent tempering that may be performed, the pore canals are closed with bar- or strip-shaped elements, which are subsequently extracted.
  22. Process in accordance with claim 21, characterized in that the bar- or strip-shaped elements are heated prior to extraction.
EP91108222A 1990-07-19 1991-05-22 Process for producing a gas purging brick with directional porosity and high infiltration resistance for metallurgical vessels Expired - Lifetime EP0467042B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT91108222T ATE103009T1 (en) 1990-07-19 1991-05-22 PROCESS FOR THE MANUFACTURE OF A RINSING STONE WITH INCREASED INFILTRATION RESISTANCE WITH DIRECTIONAL POROSITY FOR APPLICATION IN METALLURGICAL MELTING VESSELS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4022949A DE4022949C1 (en) 1990-07-19 1990-07-19
DE4022949 1990-07-19

Publications (3)

Publication Number Publication Date
EP0467042A2 EP0467042A2 (en) 1992-01-22
EP0467042A3 EP0467042A3 (en) 1992-03-18
EP0467042B1 true EP0467042B1 (en) 1994-03-16

Family

ID=6410580

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91108222A Expired - Lifetime EP0467042B1 (en) 1990-07-19 1991-05-22 Process for producing a gas purging brick with directional porosity and high infiltration resistance for metallurgical vessels

Country Status (5)

Country Link
US (1) US5225247A (en)
EP (1) EP0467042B1 (en)
AT (1) ATE103009T1 (en)
CA (1) CA2047036A1 (en)
DE (1) DE4022949C1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5554837A (en) * 1993-09-03 1996-09-10 Chromalloy Gas Turbine Corporation Interactive laser welding at elevated temperatures of superalloy articles
US5573724A (en) * 1994-07-29 1996-11-12 Magneco/Metrel, Inc. Ladle port assembly

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE821023C (en) * 1950-05-28 1951-11-15 Degussa Process for the production of highly porous moldings
US2911319A (en) * 1953-12-30 1959-11-03 Hoechst Ag Shaped bodies of carbon and process for preparing same
AT248936B (en) * 1964-11-04 1966-08-25 Veitscher Magnesitwerke Ag Process for the production of large-sized blocks made of refractory material
US3698942A (en) * 1967-10-30 1972-10-17 Dresser Ind Nozzles for continuous casting
DE1938803A1 (en) * 1968-09-03 1970-03-12 Du Pont Ceramic object and its manufacture
DD95023A1 (en) * 1972-01-26 1973-01-12
IT1034354B (en) * 1974-10-31 1979-09-10 Nippon Steel Corp METHOD FOR THE MANUFACTURING OF REFRACTORY MATERIAL THAT HAS MANY THROUGH PORES EXTENDING IN A CERTAIN DIRECTION
GB1569474A (en) * 1976-03-26 1980-06-18 Centre Rech Metallurgique Method of the quality of refractory bricks
DE3115785C2 (en) * 1981-04-18 1985-08-01 Stahlwerke Peine-Salzgitter Ag, 3150 Peine Process for the production of a gas-permeable, refractory purging stone for metallurgical purposes as well as further possible uses of a purging stone manufactured according to this process
GB2102926B (en) * 1981-06-03 1985-05-15 Nippon Kokan Kk Gas blowing nozzle, and production and usage thereof
LU85131A1 (en) * 1983-12-12 1985-09-12 Arbed GAS-PERMEABLE CONSTRUCTION BODY MADE OF FIRE-RESISTANT MATERIAL
US4851264A (en) * 1986-12-08 1989-07-25 Magneco/Metrel, Inc. Reinforcement of refractories by pore saturation with particulated fillers
DE3833502A1 (en) * 1988-10-01 1990-04-05 Didier Werke Ag GASSPUELSTEIN

Also Published As

Publication number Publication date
CA2047036A1 (en) 1992-01-20
EP0467042A2 (en) 1992-01-22
DE4022949C1 (en) 1991-07-11
EP0467042A3 (en) 1992-03-18
ATE103009T1 (en) 1994-04-15
US5225247A (en) 1993-07-06

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